1. Field
The present disclosure relates to a projection-type image display apparatus that is used for, for example, projecting a stereoscopic image using polarization.
2. Description of the Related Art
There are mainly the following three schemes for realizing a stereoscopic image. 1) A right eye-image signal and a left eye-image signal provided with parallax are respectively input to separate projection-type image display apparatuses. Images projected from respective projection-type image display apparatuses are guided to just the corresponding right or left eye using a dedicated eyewear. 2) A right eye-image and a left eye-image provided with parallax are projected while being switched at high speeds, and the images are guided to just the corresponding right or left eye using an eyewear having a high-speed shutter synchronized with the images. 3) The primary colors of an image signal are projected with waveforms being out of phase between a right eye-image and a left eye-image. For example, the right eye-image is projected while being shifted toward the short wavelength side, and the left eye-image is projected while being shifted toward the long wavelength side. By allowing the image projected by the projection-type image display apparatus to pass through an eyewear that transmits just short wavelengths, just the right eye-image can be guided to the right eye. The left-eye image is guided to the left eye in the same manner.
While these schemes each have advantages and disadvantages, particularly the scheme 1) is now the most widespread scheme for viewing with a large number of viewers because of the inexpensiveness of the eyewear, which is therefore disposable and advantageous for hygienic reasons. Unexamined Japanese Patent Publication No. 2013-120328 discloses a system employing a projection-type image display apparatus based on such a polarization eyewear scheme.